1. Field of the Invention
The present invention relates to the method of forming a transport unit by combining at least two layers each comprising an odd number of ISO-containers by the detachable coupling of corner fittings in the region of two adjacent containers having juxtaposed side walls. The corner fittings are coupled by means of coupling devices which extend into anchoring openings whereby the anchoring openings present in the upper surface of the upper central container of the transport unit are left free for the engagement of locking heads of lifting equipment.
2. Description of the Related Art
A related method is described in European Patent Application 87730069.9 (U.S. application Ser. No. 07/139,665), the disclosure of which is incorporated herein by reference. In that method, adjacent containers are coupled so that when two layers of containers are present, the containers of one layer are coupled via the lateral anchoring openings of all the adjacent corner fittings and the containers of the other layer are coupled at least via the lateral anchoring openings of the corner fittings which are present on the same level. In this manner, the adjacent corner fittings of other layers can also be coupled together.
However, as noted in the above European Patent Application, as a result of the permissible tolerances in the spaces of the anchoring openings, the lateral anchoring openings of two adjacent containers are often in positions which are so different that it is simply not possible to couple them together. Therefore, in that European patent application, it was proposed that so called double function transverse elements be used, which enable the coupling of lateral anchoring openings of adjacent corner fittings which have been considerably offset from one another lengthwise of the container.